Correlation filters are a set of synthesized spatial filters that produce controlled response with sharp peaks. Correlation filter are optimized to enhance the recognition of consistent parts while suppressing varying patterns. While providing excellent discrimination capabilities, the correlation filters also offer shift, rotation and scale invariance for 2D images.
Synthesizing the correlation filter for pattern recognition applications involve several complex mathematical operations and require high computation resources, especially for high resolution images and videos. For example, synthesis of an Optimal Trade-Off Circular Harmonic Function Filter (OTCHF) is highly compute intensive and time consuming process. Hence designing of correlation filters has limitations in pattern recognition applications which require real-time processing.